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The Bradford Factor is a formula used by HR and absence management teams to measure how disruptive an employee's absence pattern is. It was developed at Bradford University's School of Management in the 1980s, based on the idea that frequent short absences disrupt a business far more than one long absence of the same total length.
The formula is:
B = S² × D
Where S is the number of separate absence spells (instances) an employee has had over a rolling 52-week period, and D is the total number of days absent across those spells over the same period.
Because the number of spells is squared, an employee who takes many short, separate absences will score far higher than one who takes a single longer absence — even if the total number of days off is identical.
You can calculate an employee's Bradford Factor score for the last 52 weeks with our free calculator.
This is the core "aha" of the Bradford Factor — the same number of total absence days produces wildly different scores depending on how those days are spread across separate spells:
Scenario | Spells (S) | Total Days (D) | Bradford Score |
|---|---|---|---|
| One long absence | 1 | 10 | 10 |
| Ten single-day absences | 10 | 10 | 1000 |
| Five two-day absences | 5 | 10 | 250 |
There's no single universal standard, but many absence management policies use trigger points similar to these as general guidance for when to review an employee's attendance:
Score Range | Level | Typical Guidance |
|---|---|---|
| 0 – 50 | Low concern | Occasional, isolated absence. Unlikely to trigger any review. |
| 51 – 200 | Moderate concern | A pattern worth keeping an eye on. Many policies flag this for an informal chat. |
| 201 – 400 | High concern | Frequent short-term absence. Commonly the point where formal HR policies trigger a review meeting. |
| 400+ | Very high concern | Persistent, disruptive absence. Usually treated as a serious trigger point requiring formal action. |
The Bradford Factor is widely used because it's simple to calculate and highlights disruptive patterns that a simple "total days off" count would miss. But it has some well-known limitations that are worth understanding before applying it as policy:
- It doesn't distinguish between the reason for an absence — a series of short absences related to a disability or ongoing health condition can score just as harshly as unrelated, unauthorised absences.
- A high score can feel unfair to employees with legitimate, recurring health issues, so many organisations combine it with a review of the underlying reasons before taking any action.
- It only measures frequency and duration, not context such as pre-planned medical appointments or genuine emergencies.
- It should be used as a starting point for a conversation, not as an automatic disciplinary trigger.
Most HR teams use the Bradford Factor alongside their wider absence management policy, using score thresholds to flag cases for a supportive conversation rather than an automatic sanction.
Rather than calculating scores by hand, TimeKeeper automatically tracks employee absences and calculates each employee's Bradford Factor score for you as part of its leave management tools, so you can spot disruptive absence patterns as soon as they emerge.
